The present invention relates to fuel injector rails for internal combustion engines; more particularly, to devices for capturing stray fuel emissions (permeants) permeating through such fuel injector rails; and most particularly, to a system for capturing stray fuel permeants from a fuel injector rail and controllably releasing captured permeants into an engine""s air intake means.
Fuel injectors for controllably metering fuel to the combustion cylinders of internal combustion engines are well known. Modern engines typically incorporate a dedicated fuel injector for each cylinder, the fuel injector being disposed in the intake port or runner from the intake manifold to the cylinder. For ease and reliability in manufacturing, the fuel injectors typically are mounted by their inlet ends at appropriate intervals into a rigid fuel supply line harness, appropriately configured to place the injection end of each fuel injector into its corresponding injection socket in the manifold runner. Such a harness is known as a fuel injector rail, or simply a fuel rail.
Typically, the fuel injectors are sealed into the rail and into the engine by elastomeric seals such as O-rings. Such seals are excellent at preventing liquid leakage but are nonetheless somewhat permeable to hydrocarbons such as gasoline or diesel fuel, which permeation can result in environmental contamination, reduced fuel efficiency, and a potentially explosive atmosphere in the vicinity of the engine.
Also, since the fuel rails are typically exposed in the engine compartment, the rails and associated injectors are subject to water, road salt, dirt, and other contaminants introduced into the engine compartment. They are exposed to the potential of physical damage as well.
It is a principal object of the present invention to prevent escape of fuel permeants from a fuel rail into the environment.
It is a further object of the invention to increase fuel efficiency by capturing and using permeated fuel.
It is yet a further object of this invention to provide a housing in which the fuel rails and injectors reside to protect them from damage from the underhood environment.
Briefly described, a fuel rail permeant collection system in accordance with the invention includes a substantially impermeable enclosure surrounding a fuel rail for use on an internal combustion engine. Preferably, the enclosure is in communication with air intake means for the engine, for example, the intake manifold or runners from the manifold to the engine cylinders, such that fuel collected by the enclosure can be evaporated and passed into the intake means for combustion by the engine. The system may be included in a vehicle vapor purge circuit from a fuel tank emissions-control canister system.